Q. If log75=p and log102=q, solve log72 in terms of p and q
Understand Given Information: Understand the given information and what is being asked.We are given that log75=p and log102=q. We need to express log72 in terms of p and q.
Relate Logarithms: Express log102=q as an exponential equation.10q=2
Break Down Expression: Express log72 in terms of p. We need to find a way to relate log72 to log75. We can do this by recognizing that 2 is a factor of 5, specifically 5=2×(5/2). So we can write: log72=log7(5×(2/5))
Simplify Using Information: Use the properties of logarithms to break down log7(5⋅(2/5)).log72=log7(5)+log7(2/5)
Substitute Known Values: Simplify the expression using the given information.We know that 7p=5, so log7(5)=p. Now we need to express log7(52) in terms of p and q.log72=p+log7(52)
Change Base: Break down log7(52) further using the properties of logarithms.log7(52)=log7(2)−log7(5)
Simplify Further: Substitute the known values into the equation.We know that log7(5)=p, so we can substitute that in. We also know that 10q=2, which means log10(2)=q. We need to change the base from 10 to 7 for log7(2).log72=p+(log7(2)−p)
Substitute Back: Change the base of log10(2) to log7(2) using the change of base formula.log7(2)=log10(7)log10(2)Since log10(2)=q, we can substitute q for log10(2).log7(2)=log10(7)q
Final Simplification: Substitute log7(2) back into the equation for log72. log72=p+(log10(7)q−p)
Final Simplification: Substitute log7(2) back into the equation for log72. log72=p+(log10(7)q−p) Simplify the expression. Since p−p=0, we can remove them from the equation. log72=log10(7)q
Final Simplification: Substitute log7(2) back into the equation for log72. log72=p+(log10(7)q−p) Simplify the expression. Since p−p=0, we can remove them from the equation. log72=log10(7)q Recognize that log10(7) is simply the reciprocal of log7(10). log72=(1/log7(10))q
Final Simplification: Substitute log7(2) back into the equation for log72. log72=p+(log10(7)q−p) Simplify the expression. Since p−p=0, we can remove them from the equation. log72=log10(7)q Recognize that log10(7) is simply the reciprocal of log7(10). log72=(1/log7(10))q Simplify the expression by multiplying by the reciprocal. log72=q⋅log7(10)
Final Simplification: Substitute log7(2) back into the equation for log72. log72=p+(log10(7)q−p) Simplify the expression. Since p−p=0, we can remove them from the equation. log72=log10(7)q Recognize that log10(7) is simply the reciprocal of log7(10). log72=1/log7(10)q Simplify the expression by multiplying by the reciprocal. log72=q⋅log7(10) Recognize that log7(10) is a constant and cannot be simplified further in terms of log720 and log721. Therefore, the final expression for log72 in terms of log720 and log721 is: log72=q⋅log7(10)
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